Catastrophic Battery Failure

Definitely looking better!

Having the batteries on the floor between the gas tanks would be scary to me as well! You might put some thought into relocating them, IDK. Mine are under the aft dinette seat... clear of gas fumes and water.

I just did the battery replacement gig a couple weeks ago myself - ouch ($$)! They looked brand new and had always been placed on trickle-charge... but no longer able to crank the outboard. When I actually looked at the dates on the batteries, I realized they were 16 years old!!! (the boat was essentially mothballed for 8+ years).
 
With all of the other issues, I still think it was something more than corrosion caused heat generated. Certainly there was a huge surge and high heat. The "symptoms" are like a full dead short. such as the cables of positive and negative being switched....That or big voltage spike from the charger????

You may never find out.
 
I agree with Dr Bob.

Could it somehow be that a set of positive and negative cables were reversed or touching on your old switch in a position you never used until that fateful day you set the switch to "All"? I forget....was the inside of the switch all burned out too? I wonder if the fact that the switch wouldn't go past the "All" position to the "Battery 2" is a hint that something went wrong inside the switch that caused a "full dead short" as Dr Bob suggests (a fallen nut or terminal etc).

Nice job on the cables BTW.
 
thataway":1na72cux said:
With all of the other issues, I still think it was something more than corrosion caused heat generated. Certainly there was a huge surge and high heat. The "symptoms" are like a full dead short. such as the cables of positive and negative being switched....That or big voltage spike from the charger????

You may never find out.
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I tend to agree... I know batteries pretty well, and I haven't had an "aha" moment on something that would have caused it. I'm beginning to wonder if it was something internal in the battery... some sort of flaw.

Have you tried reaching out to the manufacturer? Or maybe someone who might have good contacts with the manufacturer - like a Batteries Plus store or something?
 
the engine wouldn't turn over or the gauges come on, the trim tabs, VHF and stove wouldn't power up. The fuses at the selector switch for the house system (30amp house, 10amp Wallas and 10amp VHF) were fine but when I pulled the cover over the back side of the helm station I found the trim tab (20amp) and vhf (5amp) fuses blown, same with the stove (4amp). The outboard also had a blown 30amp fuse under the cowling. After replacing all of these everything seems to be working fine. Whew!
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How would an internal short in the battery blow all of these fuses? (It would cause the explosion and high heat/fire.). The good news is that the batteries did their job, and what ever high surge there was, didn't damage the electronics..(including the electronics of the engine)...
 
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I use that Perko selector a lot to go from battery 1 to battery 2 through all. It has been getting hung up on all recently. I wonder if the switch malfunctioned and dead shorted the batteries? The switch did melt where battery one is hooked up. I haven't used my volt meter for anything other than measuring voltage since my electronics class in high school 22 years ago but isn't there a way for me to use it to check for a short across the battery switch? Theres no other way the battery wires got crossed and there was no way they were externally shorted except for possibly the switch. A surge from the charger doesn't make sense because they too are fused and the charger was actually showing a fault at battery 1. So maybe it was a combination, maybe the switch dead shorted the batteries though a loose connection at battery 1's post? I'll go figure out how to test for a short across that switch

Now that I think about it though isn't that the Perko's job? to combine the batteries? It isn't hookeld up to any negative source to short? Would it even be possible for the Perko to cause a dead short? Yea may never know ut this sure is fun.

Thanks for the conversation guys.
 
You are correct that there should be no negative side cable to the Perko switch. I have had these switches fail. But even if they were combining, both charged batteries, I would not expect that degree of heating....If the one battery had shorted internally, and then the other battery was switched, allowing full flow of the amperage to that shorted battery. If that had happened, I would not expect normal voltages in both batteries--as you found...

To check for the short put your Digital volt meter on the resistant (Ohms/Omega symbol) and set between 2K and 2M. If open it should read 1. If closed it should read 0.
 
I did have a Perko switch overheat and fail years ago. In that case it just ceased to have power at the one terminal. Plastic around it was noticeably melted and post was loose. I attributed it to prolonged cranking after running one tank out of gas(mechanical fuel pump). After that I installed an inline electric pump strictly for priming fuel from the second tank if first ran dry. No ill effects other than having to buy new switch.

Like Bob said lucky that all your fuses did their job before more damage done.

You can use the "continuity" function on a multimeter - will buzz when 2 points are connected - or the ohm meter.

Regards,

Rob
 
Took the boat out twice since our mishap and everything seems to be running great. Here's to luck that it wasn't worst and now its better than new!!
 
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